5. Installation
5.1. LAYING TIMBER FLOORING
Adequate lighting should be provided when laying
timber flooring. Timber strips that are slightly out
of alignment may show up distinctly when lighting
falls on them, helping the installers to spot any
misalignment of the timber strips.
Table 5.1 summaries the good practices in laying
different types of timber flooring systems.
Table 5.1 Installation of Timber Flooring
Preparing and Laying Timber Flooring
Preparatory works for laying over plywood (for plywood sub-base method)
1.1.1
Remove any dirt and dust on the screed.
1.1.2.
Apply adhesive according to manufacturer’s instructions.
–
When spreading the adhesive, only
apply sufficient amount of adhesive
that the plywood can be laid on within
the open-time of the particular
adhesive.
1.1.3.
Lay plywood and fasten the plywood with concrete nails at
300mm centre-to-centre space interval.
–
Stagger the plywood joints.
–
Provide 2-5mm gap between plywoods
and 6-8mm gap between plywoods
and perimeter walls.
–
Ensure the plywood is firm and stable
with no movement when walking
on it.
1.1.4.
Allow the adhesive to fully cure before proceeding to install
timber flooring.
1.1.5.
Clean away any dirt and dust on the plywood before
installation.
installation
1.1
Remarks
12
Preparing and Laying Timber Flooring
1.2
1.2.1.
installation
2.
Remarks
Preparatory works for laying of timber flooring (for direct installation method)
Remove any dirt and dust on the screed.
– It is a good practice to vacuum the
screed surface as any presence of
granular particles trapped between the
timber strips may cause inconsistent
joints.
Laying timber flooring
2.1.
Apply adhesive according to manufacturer’s instructions.
2.2.
Lay timber flooring. Where possible, use a floor nailing
machine after the second or third run is in place.
–
Laying directly over screed using adhesive; or
–
Laying over plywood with tongue and groove.
– When spreading the adhesive, only
apply sufficient amount of adhesive
that the timber flooring can be laid on
within the open-time of the particular
adhesive.
– Where appropriate, maintain full width
of timber strip at the door entrance or
as per approved shop drawings.
– The use of nailing machine is preferred
as it drives nails mechanically or
pneumatically through the tongue of
the flooring at proper angle.
– Avoid nailing into the plywood joints.
Position the floor strips so that they
do not meet at the plywood joints.
– To minimise inconsistent joint, timber
strips should be “pressed-in” to
enhance bonding and close up the gap
between the strips.
– Wedges should be provided at the
perimeters of the room to prevent any
movement during the curing process.
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Preparing and Laying Timber Flooring
–
Remarks
Leave expansion gap of 6-8mm at the perimeters of the room.
2.3.
Allow the floor to cure for a minimum of 3 weeks (or period
specified by manufacturer). Restrict access to the area during
the curing period.
– For proper curing, flooring should
not be covered during the curing
period. Do not allow anything to
spill on the timber flooring as this may
contaminate the final finishes.
2.4.
Remove perimeter wedges and check for loose timber strips.
– Rectify any loose timber strips according
to manufacturer’s instructions.
installation
– All wood products expand and contract
with humidity changes. The expansion
gap provided will allow for such
dimensional changes.
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5.2. SANDING
The timber floor should be sanded before applying
the finishing coat to give a smooth and level surface.
The number of sanding operations depends on the
type of timber flooring and the level of unevenness
of the floor. Manufacturer’s advice should be consulted
on the number of sanding operations required.
Normally, 3 to 4 sanding operations are required. The
1st sanding should produce a level and completely
sanded surface. Subsequent sanding operations would
then serve to remove the sanding scratches produced
by the 1st sanding. Table 5.2 shows the commonly
used floor sanding grits defined by NOFMA*: The
Wood Flooring Manufacturers Association and Table
5.3 shows good work practices to be adopted when
sanding timber flooring. Unless otherwise specified
by the manufacturer, the sanding sequence shown in
Figure 5.1 should be followed.
Table 5.2 Commonly used Floor Sanding Grits
Classifications
Sanding Grits
Coarse
Medium
Fine
Very Fine
36,40
60,80
80,100,120
120,150
Source: NOFMA
1st sanding (either directions)
1st sanding
3rd sanding
installation
light incidence
2nd sanding
subsequent sanding operations
Sanding Sequence for Parquet Flooring
Figure 5.1 Sanding Sequence for Timber Flooring
*NOFMA - National Oak Flooring Manufacturers Association
15
Sanding Sequence for Timber Strips Flooring
Table 5.3 Sanding Timber Floor
Sanding Timber Floor
Remarks
1. Before commencement of sanding, check for any protruding nail
heads and remove them.
–
Sanding on exposed nails may produce
sparks and cause a fire in the sander
dust bag.
–
It is important that the correct type of
sand papers are used for the various
rounds of sanding.
–
Sand paper should be changed when
necessary. Some timber species are
highly resinous and tend to clog
sandpaper. When working on such
species, change the sandpaper more
often.
–
At areas such as corners or edges of
walls where the sanding machine
cannot be reached, edge sander should
be used.
–
The wood filler could be prepared by
mixing the sanding dust of the last
sanding operation and a gap filling
adhesive solution. This filler should
has a shade as close to that of the wood
surface as possible.
3. Start the sanding operations. Clean the surface with a vacuum
cleaner following each sanding operation.
4. Where applicable, apply a coat of wood filler to patch up nail holes
and gaps, prior to the last sanding operation.
installation
2. Clean the floor with a vacuum cleaner.
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5.3. APPLYING FINISHING COAT
Immediately after sanding is completed, the finishing
coat should be applied. This will protect the exposed
timber from getting dirty and absorbing excessive
moisture. Finishing coat provides a uniformly enhanced
surface and seals the timber flooring against moisture
and foreign materials. Manufacturer’s instructions and
recommendations should be followed when applying
the finishing coat. Table 5.4 shows the steps required
to achieve good timber flooring when applying the
finishing coat.
installation
Table 5.4 Applying Finishing Coat
Applying Finishing Coat
Remarks
1. Sweep and vacuum the floor. Wipe and remove all dust on windows,
doors, door frames, expansion gaps etc.
–
If surface is not properly cleaned, sand
or dust may get stuck on the finishing
coat and result in roughness of the
finished surface.
2. Apply the finishing coat evenly with a surface brush or a roller.
–
The manufacturer’s guide on coverage
should be strictly followed.
–
Start on the side of the light incidence
and work away from the light. This
allows better observation of the
finished surface to spot and rectify any
possible imperfections.
–
When applying finishing coat, avoid
direct sun radiation on the surface as
radiation may lead to the generation
of blisters in the finishing coat.
–
–
applying finishing coat with a surface brush
applying finishing coat with a roller
3. Allow the finishing coat to dry according to manufacturer’s
instructions.
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Remarks
4. If abrasion is specified by designer, sand the flooring using a finishing
sander with sand paper of very fine grit such as 150/180.
–
This sanding is to remove all risen
wood grain and to smoothen the
flooring.
5. Clean the flooring with a vacuum cleaner. Wipe and remove all
dust on windows, doors, door frames etc.
–
This is to make sure no dust is stuck
on the newly finished surface.
6. Apply the second finishing coat according to the same application
procedure for the first coat.
–
To enhance the resistance of the timber
flooring, a third coat may be applied
in the same way after the floor is dry.
7. Leave the finished flooring to cure for minimum 7 days (or follow
manufacturer’s recommendation) before covering or protecting the
surface. During this curing period, restrict access to the room.
installation
Applying Finishing Coat
5.4. INSTALLING TIMBER SKIRTING
The installation of skirting involves using adhesive
and concrete nails to secure the skirting in place (see
Figure 5.2). The nails could be temporarily or
permanently secured to the skirting. For temporary
securing, the nails should only be partially hammered
in to facilitate easy removal at a later stage. For
permanently securing, headless concrete nails should
be used. Thereafter, nail holes should be concealed
with matching wood filler and sanded smooth before
finishing.
Figure 5.2 Installation of Timber Skirting
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5.5. INSPECTION
Close supervision should be provided for both
in-process and finished works. In order to achieve
high workmanship quality, it is important that quality
control should be driven by the site management.
Site supervisors and installers should be adequately
trained and display competency in their works. Quality
control starts with good planning. It is a good practice
to prepare an Inspection and Test Plan, ITP (see
Appendix B) which summaries the project’s inspection,
acceptance criteria and the frequency of inspection.
Appendix C shows a sample of inspection checklist
for laying timber flooring. Site supervisor should carry
out in-process inspection to ensure the steps are
properly executed. Holding points should be set at
critical stages where unsatisfactory work can be rectified
before proceeding to the next stage of work.
The finished works should be inspected to ensure they
meet the client’s requirements and standards. Table
5.5 shows a recommended checklist for final inspection
of timber flooring. The inspection criteria in the
checklist are in accordance with the CONQUAS 21
quality assessment standards.
Table 5.5 Checklist for Final Inspection of Timber Flooring
Inspection Checklist
1.
1.1.
CONQUAS 21 Assessment – Jointing
No visible gap between timber strips
installation
✓
Good jointing
1.2.
✗
Obvious gaps between timber strips
Edges of the flooring to be properly sealed
✓
1.3.
No visible gap between skirting and wall/ timber flooring
✓
No visible gap between skirting
and timber flooring
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✗
Uneven gap between skirting
and timber flooring
Inspection Checklist
2.1.
CONQUAS 21 Assessment – Finishing
No stain mark
✓
Good surface finishes
2.2.
✗
Paint stain
Consistent colour tone
✓
Consistent tonality
– pattern and shades are well blended
3.
3.1.
✗
Inconsistent tonality
CONQUAS 21 Assessment – Alignment & Evenness
Surface are even (not more than 3mm over 1.2m)
✓
Evenness ≤ 3mm per 1.2m
4.
4.1.
✗
installation
2.
Evenness > 3mm per 1.2m
CONQUAS 21 Assessment – Cracks & Damages
No crack and other visible damage
✗
Crack
✗
Dent
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